Parasitology Commons^™

In Sickness And In Health: Parasites Of Stranded Pacific Harbor Seals (Phoca Vitulina Richardii) In Northern Oregon And Southern Washington, Cecily Douglas Bronson

Dissertations and Theses

Parasites have the capability to infect virtually every living organism on the planet and have adapted to infiltrate every trophic level. Many species have complex indirect life cycles and rely upon hosts at different levels of the food web for growth and reproduction. In the marine environment, having a high level of parasite diversity is thought to indicate a more stable ecosystem than an environment with low parasite diversity. As one of the top predators in their environment and because of their amphibious behaviors, pinnipeds (seals and sea lions) are exposed to a wide variety of parasites, making them ideal …

Multiple Acquisitions Of Pathogen-Derived Francisella Endosymbionts In Soft Ticks, Jonathan G. Gerhart, H. Auguste Dutcher, Amanda E. Brenner, Abraham S. Moses, Libor Grubhoffer, Rahul Raghavan

Biology Faculty Publications and Presentations

Bacterial endosymbionts of ticks are of interest due to their close evolutionary relationships with tick-vectored pathogens. For instance, whereas many ticks contain Francisella-like endosymbionts (FLEs), others transmit the mammalian pathogen Francisella tularensis. We recently sequenced the genome of an FLE present in the hard tick Amblyomma maculatum (FLE-Am) and showed that it likely evolved from a pathogenic ancestor. In order to expand our understanding of FLEs, in the current study we sequenced the genome of an FLE in the soft tick Ornithodoros moubata and compared it to the genomes of FLE-Am, Francisella persica—an FLE in the soft tick Argus (Persicargas) …

The Response Of Mice To Infection By The Parasitic Nematode Trichinella: A Comparison Of Trichinella Spiralis And Trichinella Pseudospiralis, Barry Clayton Anderson

Dissertations and Theses

The intracellular parasite Trichinella is a genus in phylum Nematoda that contains six named species including Trichinella spiralis and Trichinella pseudospiralis. These parasites infect a large variety of wild and domestic animals, human beings and a few species of birds. The parasitic strategies and the pathological effects on the host between trichinella spiralis and Trichinella pseudospiralis are quite different.

The purpose of this study is to gain an understanding of the physiological, immunological and pathological differences between these two species of Trichinella using infections in the mouse as a model. In the course of this research I have attempted to …

The Life Cycle Of Lissorchis Heterorchis, Macy And Krygier (1969), Brendan P. H. Onyejekwe

Dissertations and Theses

Many Flumenicola virens (Lea) collected from Crystal Springs Creek and Tualatin River, Portland, Oregon, were found to shed large numbers of a species of microcercous cercariae containing refractile granules. They resembled the cercariae of Triganodistomum mutabile (=Lissorchis mutabile Cort, 1918 as described by Wallace (1939), and subsequent experiments proved that they were the larval stages of what was described by Macy and Krygier (1969), as Lissorchis heterorchis. Encystment of these cercariae was induced experimentally in uninfected adult brown planarians collected partly from Crystal Springs Creek and partly from Carolina Biological Research Station in Gladstone, Portland, Oregon. Adult flukes …

Life History Of Philophthalmus Megalurus (Cort, 1914) In Western Oregon, Toni Anne Mcmillan

Dissertations and Theses

The specific identification of a megalurous cercaria found in the snail Oxytrema plicifera was accomplished by completing the life cycle in the laboratory. This species is compared with the eastern Philophthalmus megalurus and P. gralli with which it was once confused. The eggs, miracidia, and rediae of the Oregon species were found to be similar to those of the above species. The body and organ sizes and sucker ratios for the cercariae and adult stages obviously indicate that the Oregon species is Philophthalmus megalurus.